Handling Telnet URLs with Iceweasel / Firefox

I needed to find a way to launch telnet sessions from a webpage URL using the Iceweasel (Firefox) browser on my Debian GNU/Linux workstation. This simple task proved to be quite time consuming, as a lot of the HOWTOs out there were (at the time of writing) relying on obsolete information.

By default if you try an open a link similar to telnet://name on Debian using Iceweasel you will get the following error message:

Firefox doesn’t know how to open this address, because the protocol (telnet) isn’t associated with any program.